Bioactive Secondary Metabolites from Trichoderma spp. against Phytopathogenic Bacteria and Root-Knot Nematode

Abstract

Losses in crops caused by plant pathogenic bacteria and parasitic nematode are increasing because of a decrease in efficacy of traditional management measures. There is an urgent need to develop nonchemical and ecofriendly based management to control plant diseases. A potential approach of controlling plant disease in the crops is the use of biocontrol agents and their secondary metabolites (SMs). Luckily fungi and especially the genus Trichoderma comprise a great number of fungal strains that are the potential producer of bioactive secondary metabolites. In this study secondary metabolites from ten Trichoderma spp. were evaluated for their antibacterial and nematicidal potential against phytopathogenic bacteria Ralstonia solanacearum, Xanthomonas compestris and plant parasitic nematode Meloidogyne incognita. Five different growth media were evaluated for the production of SMs. It was shown that SMs of different Trichoderma spp. obtained on different growth media were different in the degree of their bioactivity. Comparison of five growth media showed that SMs produced on solid wheat and STP media gave higher antibacterial activity. SMs of T. pseudoharzianum (T113) obtained on solid wheat media were more effective against the studied bacteria followed by SMs from T. asperelloides (T136), T. pseudoharzianum (T129) and T. pseudoharzianum (T160). Scanning electron microscopy (SEM) was further conducted to observe the effect of SMs on bacterial cell morphology. As evident from the SEM, SMs produced severe morphological changes, such as rupturing of the bacterial cell walls, disintegration of cell membrane and cell content leaking out. SMs from T. viridae obtained on liquid STP and solid wheat media showed the highest percent of M. incognita juveniles (J2s) mortality and inhibition in egg hatching of M. incognita. The results of our study suggest that T. pseudoharzianum (T113) and T. viridae could be selected as an effective candidate for SMs source against phytopathogenic bacteria and M. incognita respectively.

Effect of Colonization of Trichoderma harzianum on Growth Development and CBD Content of Hemp (Cannabis sativa L.)

“…The interaction of the fungus with roots is a complex framework that includes several secondary metabolites secretion, rapid metabolomic alterations, and biochemical pathway triggers. Trichoderma harzianum utilization could be extended beyond its typical use as a biological agent of pesticides against several plant diseases [ 84 , 85 ] and be integrated as a component of integrated fertilization programs [ 86 ] for sustainable crop production of major field and industrial crops, such as hemp. This study reveals that Trichoderma harzianum can significantly improve hemp production without the combined application with AMF [ 46 , 87 ].…”

Bioactive Secondary Metabolites from Trichoderma spp. against Phytopathogenic Fungi

“…The inhibition of B. cinerea spore germination has been shown to be due to the synergetic effect of gliotoxin ( Figure 1 ; 1) and endochitinase enzymes [ 109 ], while gliP- deleted mutants of T. virens , which are unable to produce gliotoxin, reduced their mycoparasitism against the soybean pathogen S. sclerotiorum and oomycete pathogen P. ultimum [ 27 ]. Similar to other plant beneficial microorganisms, Trichoderma fungi release elicitor-like substances which induce a systemic or localized resistance response in plants [ 5 ].…”

“…Using gene disruptions, the 18-residue peptaibol synthetase Tex1 has been shown to be responsible for the production of the trichovirin II-type 18-residue peptaibol, while the 14-module enzyme assembles both the 14-residue and the 11-residue peptaibol in T. virens [28,51,52]. [5] trichokonin VII, [6] trichokonin VIII, [7] trichorzianine A1, [8] trichorzianine B1, [9] peptaivirin A, [10] peptaivirin B; peptaibols [4], [5], and [6] were isolated from T. koningii, [7], [8], [9], and [10] were isolated from T. harzianum.…”

“…Secondary metabolites (SMs) from microorganisms may have an antifungal role against agriculturally important phytopathogenic fungi [ 4 ]. Among different microorganisms, the species of the genus Trichoderma are the most potent biocontrol agents in use today because they produce a diverse range of antimicrobial SMs [ 5 , 6 ]. Trichoderma species secrete a plethora of metabolites into their vicinity while having minimal nutritional needs.…”

Biocontrol of economically important weed species through endophytic fungi isolated from Parthenium hysterophorus (Family: Asteraceae)

“…Among microbial communities within the plants, the fungal community and especially endophytic fungi play a dramatic role in the physiology of their host weed plants and also produce and/or induce plants to produce phytotoxic compounds or other metabolites that have activity against other weeds, insects, and fungal pathogens (Khan et al 2020a;Khan et al 2020b). Hence, the main sources for the discovery of novel biologically active compounds are from endophytes.…”